Berenbaum's online

At 4:30 a.m. on a Saturday in early winter, Downtown Durham is a dark, cold, empty place. But if you walk through certain half-deserted streets, you'll find lights and life glowing purposefully at Rue Cler, Scratch and Daisy Cakes. At Loaf, proprietor Ron Graff is working his dough, his back to the door, his long ponytail silver-lit and perfectly framed between the tall baking racks.

Three blocks away, Ari Berenbaum is working inside Ninth Street Bakery. Berenbaum was the head baker here for about 18 months in 2009 and 2010. Although he is no longer in Ninth Street's employ, by special arrangement he still uses the facilities for his eponymous, mostly Jewish bakery, which has been in business for about a year.

Berenbaum's website describes it as "a data-driven, open-sourced, sliding-scale food concept." The front page adds, more practically: "Currently our stand is situated near the Durham Farmers' Market." (Berenbaum has an application pending with the DFM board for a vendor spot.) Most Saturdays, catty-corner to the market pavilion at Foster Street and Hunt Avenue, the modest stand does a brisk business in handmade baked goods, coffee and, sometimes, a peculiarly addictive chai-like tea.

The "sliding-scale" part of Berenbaum's concept emerges after customers enjoy a free sample and choose to make a purchase. They're told that each buyer sets the price. Watching this moment repeatedly, it seems that nothing is guaranteed to flummox an American quite like variable pricing: Our consumer rabidity makes us, paradoxically, deeply biddable. Witness the Berenbaum's customer pause blankly, as though mentally translating a foreign language, then raise a "what's the catch?" eyebrow or laugh uneasily—or, in one memorable moment, level a reactionary accusation of communism.

Finally, the customer will ask, even beg, for a suggested price, which Berenbaum happily provides (for most whole loaves, around $4–$5). "We're not out to stump anyone," Berenbaum's website insists. On the contrary, the "open-sourced" part of the concept entails transparency and inclusiveness, and Berenbaum's blog is pleasingly candid.

"I want anyone who would like to eat our bread to eat our bread, even if they have no money," Berenbaum says. "We often give away loaves to people who have no remaining market cash, typically only on the verbal promise that they come back next week and buy something or 'like' us on Facebook" (where there is also a weekly giveaway winner). Berenbaum also offers a "CSB"—Community Supported Bakery—that delivers by bicycle on Saturdays in West Durham, also on a sliding scale.

Before Berenbaum worked at Ninth Street Bakery, he was a graduate student in the sociology department at UNC-Chapel Hill. Hoping to find sponsorship for doctoral research, he wrote a monograph on the French post-structuralist theory collaborators Gilles Deleuze and Félix Guattari. Deleuze and Guattari, conventionally often called just "Deleuze," are notorious for the difficulty of their writing, and at certain kinds of cocktail parties they provide a reliable punch line for zingers about abstruse theoretics.

Yet Berenbaum's monograph, called "A Crystalline Castle," earnestly attempts to apply Deleuze to the practicalities of the social sciences—schizophrenia appears to be an underlying concern—and it is textured with examples to give the reader a foothold. Touchstones include Jorge Luis Borges' "The Garden of Forking Paths," the Charlie Chaplin movie Modern Times and pop culture figures such as skateboarding legend John Cardiel and rapper Ghostface Killah. Berenbaum's prose is friendly, evenhanded and reassuring: "If you cannot read a work of Deleuze word for word," he adjudicates, "there may be nothing wrong with Deleuze, and there is certainly nothing wrong with you." It's Deleuze as sliding-scale theory.

Nonetheless, "A Crystalline Castle" is a stiff challenge. It isn't meant for the common reader—but it didn't sit well with the tweed-jacket set, either. Numerous scholars uniformly rejected Berenbaum as a potential Ph.D. candidate, sometimes quite brusquely. "People can get real personal about this author," Berenbaum deadpans.

So he left academia and went into baking. Since leaving Ninth Street Bakery and hanging out his own shingle, Berenbaum's weekly offerings have increasingly celebrated the traditional Jewish breads and pastries he grew up eating. Last month, Berenbaum was invited to sell his poppyseed babka in a sort of pre-Hanukkah bazaar at the Levin Jewish Community Center in west Durham. The clientele base there needed no babka tutorial ("This takes me back to my childhood!" exclaimed one older gent, happily munching on a sample). Instead, the first question tended to be a much more pointed one: "Is it parve?" They did, however, need help with the sliding-scale concept: One thirtysomething mom, when informed that the price was up to her, stiffened in alarm and retorted, "That's a terrible thing to say to a Jew!"

Uncomfortable racial and cultural subtext lurks in the connotations of a Jewish bakery that allows customers to manipulate their own price. Berenbaum is aware of that, but he isn't really interested in "theory production." He mostly just wants to bake, and declares—in his typical playful deadpan, which crusts his wit in golden-brown appeal—that "the customer is not a commitment."

That's an odd watchword for a businessman, and in fact Berenbaum is keenly interested in consumer habits. He worked for a while at a Barnes & Noble café, and found that "as evil as a big-box bookstore is, it taught me a lot of operational crap—selling, product placement, getting inside the mind of the bourgeois shopper—that I otherwise never would have learned. I think everyone who wants to own their own business should work in a situation where they might do 400 transactions at a till in a day next to an 'impulse aisle.'"

But when it comes down to it, Berenbaum concludes, "this is a pop-up experimental bake stand. We live to experiment and try new recipes."

At 5:15 on this Saturday morning, that's what he's doing. Berenbaum stands assessing the dough for his vollkornbrot, a traditional whole-grain German rye bread, with Alex Ruch, his primary collaborator. Ruch, a slender, elfin guy with a touch of mischief about him, has more than baking in common with Berenbaum: He, too, came from the unlikely realm of postmodern philosophy. Ruch received his doctorate in literature from Duke. (Coincidentally, Ruch's undergraduate thesis is partially about Deleuze and Guattari.)

For the vollkornbrot, the two philosopher-bakers have used Ruch's starter, which he keeps and tends in his home refrigerator. Satisfied with the dough's texture and tang, they roll it out, shape it into loaves and move it to the proofing box, then turn their attention to chocolate babka assembly.

Central to "A Crystalline Castle" is the slippery Deleuzian concept of "immanence." Berenbaum correlates immanence to Borges' "Garden of Forking Paths," in which the infinite outcomes of a given event occur simultaneously in a time continuum. "Immanence is the moment when there is no outside to the moment ... the wormhole, the rabbit hole," Berenbaum expands on one of his three blogs. "The feeling of happiness, or even jouissance, can be achieved via the pursuit of immanence."

A 1-pound chunk of dough is rolled out, layered with chocolate paste, rolled up and tucked into shape, then set gently in its rectangular pan on a rectangular rack. The bakers fall silent as they work, in trance-like meditation. An hour vanishes, and then there are dozens of them: a stacked multiplicity, a delighting infinity of babkas. Immanence. Manna.

Up and out of the rabbit hole of Ninth Street Bakery, it's 7 a.m. A few early risers tread the downtown Durham sidewalks. Cars creak by on the streets. The world that was in darkness has grown light. The day, like bread, is rising.